The invention concerns the field of network management, and more particularly concerns determining the locations of network devices that are unable to access satellite positioning systems such as GPS because of shielding by buildings.
Internetworks and intranetworks have become exceedingly complex, and therefore hard to manage. Thus, in order to enable a network operator to manage such networks effectively, advanced network management systems provide the operator with a simplified graphical visualization of the network. Traditionally, this is done using layout algorithms that place the network devices in circles, in trees, and the like.
Technology has existed for some time to lay out network devices in such a visual display using the latitudes and longitudes of the devices. However, in practice this has not been useful, because there has been no effective way to gather the needed coordinates.
Although in principle a network device could be equipped with Global Positioning Satellite (GPS) capability to determine its location, GPS has a low RF link margin, and therefore cannot be used reliably to determine locations of network devices that are used indoors. Unfortunately, many network devices of practical interest are indeed used indoors routinely. These include, for example, network devices inside offices and laboratories, local area network (LAN) closets, data centers, and so forth.
Of course, the needed coordinates could be manually determined and manually entered into a network management database. Such a process, however, is not only impractical in large scale networks, it is also time consuming, error prone, and subject to constant revision as the locations of network devices change.
Thus, there is a need for a way to automatically determine and track the locations of network devices that are used in environments which are inaccessible to GPS signals, for the benefit of network management systems.